Mold and method for making a dome structure



J. C. A. M MILLAN MOLD AND METHOD FOR MAKING A DOME STRUCTURE Filed Aug.1, 1956 Nov. 8, 1960 2 Sheets-Sheet 1 FIG. 5.

INVENTOR.

JANE?- C 24. N146 N/Z. Z. A/V

BY W W ATTOP/VE rs Nov. 8, 1960 J, c, amlLLAN 2,958,918

MOLD AND METHOD FOR MAKING A DOME STRUCTURE Filed Aug. 1, 1956 2Sheets-Sheet 2 INVENTOR.

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Patented Nov. 8, 1960 MfiLD-AND METHOD FOR MAKING A DOME STRUCTURE Thepresent invention relates to structures of domelike configuration andparticularly to a method and novel mold assembly for producing aplurality of curved segm'ents capable of being fitted together to forman inhabitable dome-like structure or construction toys such as, toyigloos and the like.

Recent trends in the do-it-yourself field have opened up new avenues ofapproach in the field of buildingconstruction enabling home owners toput together prefabricated segments or units to form desirablestructures, such as breezeways, sheds, small country cottages, etc. Thepresent invention which relates to dome-like structures is particularlyapplicable to the new do-it-yourself trend. The invention is alsoapplicable to the held of educational toys of the three-dimentional'puzzle variety.

Construction toys generally comprise rectangularly configurated' blocksfrom which rectangular structures are then constructed. However, in thegeneral toy field not much has been done with the construction ofdome-like structures from curved building block segments. Apparently thereason for this is because it is difli'cult to produce such segments orelements economically which can then be fitted together to produce adome-like structure. Suchsegments would have to be curved in threedimensions and would have to be made sufiiciently accurate so that theparts can be fitted together easily by children. This also holds truefor the construction of inhabitable structures.

It is the object of the present invention to provide a novel moldassembly which; enables the production of curved building block segmentsrequired to form a single dome-like structure.

Another object of the present invention makes possible the provision ofthree-dimensionally curved; segments which are fittable together to forma curved dome.

A further object of the present invention is to provide curved segmentswith connecting means whereby when the curved segments are fittedtogether, the resulting structure will be rigid;

Still another object of the invention is to provide a toy igloocomprising a plurality of fittable, three-dimen: sionally curvedbuilding block segments.

A further object of the invention is to provide a method whereby all ofthe curved segments can be produced from a single mold in one operation.

These and other objects will more clearly appear when taken inconjunction with the following description and the I accompanyingdrawings wherein:

Figs. 1, and 2 show the elevation and top views respectively of an iglooshaped structure produced from three-dimensionally curved segments;

Figs. 3 and 4 are examples of the type of segments which are,employed'in producing the dome-like structure;

Fig. 5 is illustrative of connecting means which may be employed to fitvarious curved segments together in producing a rigidly constructeddome;

Fig. 6 shows another embodiment similar to Fig. 5;

Fig. 7 is a phantom view of a flexible rubber-like mold- 2 comprising aplurality of. manipulative mold compartments from which a plurality ofthree-dimentionally curved segments can be produced and thereafterfitted together to form a dome-like structure;

Figs. 8 and 8a show a partial and phantom view of.

another type of'moldcomprising a rigid,.segmented' outer shell and' aflexible, manipulative inner membrane that can be employed in carryingout the invention;

Figs. 9. and 9a illustrate male and female die molds, respectively,which may be employed in producing'igloo type structures; and

Figs. 10 to 14 show embodiments. of connecting means which may beemployed in connecting curved segments in the production of'rigid,inhabitabl'e structures, Fig. 14'

being a section through Fig. 13.

Referring to the drawing, Figs. 1' and 2 show a toy igloo produced inaccordance with the invention comprising a dome-like portion 1 andanentrance portion 2. The dome-like portion 1 is made up of a plurality ofthree-dimentionally curved segments such as segments 3' and 4' which areshown separately in Figs. 3 and 4 respectively. The segments arecharacterized by transverse topand bottom portions 321 and 3b as shownin Fig. 3, or 4a and 4b as shown in Fig. 4. The top and bottom portionsare referred to broadly as flat supportable base portions of curvilinearcontour, the fiat surface lying in a plane which passes transverselythrough the polar axis of the. dome-like structure produced when thecurved segments are assembled together. The curved segments are alsocharacterized by flat side portions 3c and 321 as shown in Fig. 3, orside portions 40 and 4d as shown in Fig. 4, the flat side edges alsobeing of curvilinear contour and the fiat side surface lying in planeswhich contain the. polar axis of said dome-like structure. The polaraxis referred to would be the axis A-A as shown in Fig. l of thedome-like igloo. When the curved segments are configurated as describedabove by molding, they are easily assembled together side by side andone on top of another to form an accurately assembled domelikestructure. The top of the dome may comprise a cap 4e as shown in Fig. l,or triangular curved segments fitted together to. form a cap.

If a rigid structure is desired capable of withstanding vibrationaldisturbance within its immediate environment, connecting means may beutilized; between adjacent coinciding fiat base portions of thesegments. This is illustrated with particularity in Figs. 5 and 6 of thedrawing. Fig. 5 shows a bottom curved segment 7 and 7a having tworecesses. 9 and 9a. which are directly below two connecting means orprojections 8' and 8a projecting downwardly from two curved segments 5and 6, respectively. In Fig. 6 a similar structure is formed with theexception that the recess 14 is made up of two recessed portions, one insegment'10 and the other in segment 11, the recess spanning the juncturebetween the coinciding face 15 of segments 10. and 11. Recess 14 isadapted to receive connecting means ifiprojecting downwardly from curvedsegment 12. Of course, it will be appreciated that various types ofconnecting means can be employed to insure rigid dome-like structures aswill be described later.

Fig. 7 illustrates one type of mold assembly comprising a flexible shell16 having arranged internally thereof horizontal flexible partitionrings 17, 18 and 19 intersecting with vertical ribportions 20 arrangedpretty much as great circles are arranged within the interior of a'hollow sphere; The intersections of the horizontal rings and verticalpartitions form a plurality of manipulative mold compartments orsections corresponding to the shape of segments 3, 4, etc., of Figs. 1to 4. The mold compartments in the flexi: ble mold are filled with asettable material such as plaster of Paris and the exposed face of thematerial smoothed out with a spatula flush with the top of thepartitions. and

then allowed to set. After the material has hardened the mold need onlybe flexed by manipulation with the hands to dislodge the various curvedsegments which are then ready for assembly into a dome-like structureconforming to the internal configuration of the rubber-like mold.

If desired, the mold can be produced with a hard or rigid outer shellcomprising manipulative lunar-type sec tions 21, 22, etc., as shown inthe sectional view of Fig. 8. Integral with the side faces of the moldsegments are formed vertical ribs or partitions such as 23 and 24, whichabut against horizontal partition ribs, such as 25 and 26, to form thedesired mold compartments in which the curved segments are produced.This is illustrated more clearly in Fig. 8a which shows the edge of thehorizontal partitions flush with the side edge 26a of the mold section.In other words, the horizontal partitions are segmented so that the moldsections are manipulatable via the rubbet-like coating bridging theedges of the partitions. The partitions may be made of flexiblematerial. However, in this case the inner portion of the rigid moldassembly is preferably completely sprayed with an elastic rubberlikematerial 23a, for example Latex, which forms a thin stretchable membraneagainst which the settable material is cast and smoothed within each ofthe mold compartments. When the settable material has hardened, therigid mold sections 21, 22, etc., are caused to move slightly outward byhand manipulation thereby causing the thin rubber-like membrane tostretch and dislodge from the mold compartments the hardened pieces ofsettable material. The mold assembly of Fig. 8 has the advantage overthe mold assembly of Fig. 7 in that during its use the surface of theelastic membrane can be maintained somewhat rigid by virtue of thebackup support of the rigid mold sections thus assuring moreaccurately-shaped segments.

The expression rubber-like as employed herein is meant to includematerials with at least some elasticity when subejcted to distorting orwarping stresses. Such material may have a rubber base or a plasticbase, particularly those plastic materials frequently referred to asartifical rubber. Latex is particularly useful when employed as adistortable membrane in combination with a back-up support. Examples offlexible plastic materials are elastomeric plastics such aspolyethylene, styrene and butadiene co-polymers, styrene polymers, etc.

The thin flexible ribs which define the mold compartments may likewisebe made of rubber-like material, although flexible plastic materialssuch as nylon may be used. In some instances fairly rigid portions maybe employed, such as curved aluminum strips, etc. The thickness of thepartition n'bs may range from about 0.005 to one-thirty second of aninch. When producing large curved segments, thicker partitions may beemployed.

As illustrative of the mold combination which may be employed to produceigloo-type structures, reference is made to Figs. 9 and 9a which show amale and female mold die respectively. Fig. 9a shows a partial view ofthe female mold comprising outer supporting segments 27, 28, 29, etc.backing up three-dimensionally curved mold segments 30, 31, 32, etc.showing partition lines 33, 35, etc. bounded interiorly by verticallydisposed partitions 34 and horizontal segmented partitions rings 36, 37and 38 which meet at said partition lines. As will be noted, theintersection of the horizontal and vertical rings result in a pluralityof mold compartments, each capable of forming a three-dimensionallycurved segment. The portion defining the entrance of the igloo is showngenerally at 39 as comprising an arch portion 40 and side wall portions41 and 42. Horizontal ring 36 connects with the entrance por tion viapartitions 43a and 431;. Two other partitions 44a and 44b runningtransverse to U-shaped partition 45 are also shown. Thus, this portionof the die is adapted to produce three entrance segments comprising anarchway such as 2a of Fig. l, and two side supports such as 2b also ofFig. 1. In producing a toy igloo by a segmented mold of this type, it isdesirable, though not essential, to coat the whole inner molding face ofthe mold including the partitions with a rubber-like membrane 46 similarto membrane 23a of Fig. 8, of sufficient elasticity so that when aplurality of curved building segments are formed in the moldingcompartments, they can be easily removed by manipulating the moldingsurface segments (30, 31, 32), in this case by drawing the outerintegral supporting segments 27, 28, 29 outward sufficiently to subjectthe inner rubber-like membrane covering the mold segments to distortion,thereby loosening the formed material and enabling it to be removed.

In producing an igloo, the molding material, such as a soft putty-likemixture of plaster of Paris is poured into the compartments of the mold,including the igloo entrance portion, smoothed in place to the top levelof the partitions, allowed to set, and then removed by merelymanipulating the mold segments to stretch or distort slightly therubber-like membrane, thereby loosening the cast segments. The curvedpieces are easily fittable together to form an igloo-like structure.

Another method for producing the igloo-like structure is by using acombined male and female die mold, the male die mold being shown in Fig.9 as comprising a dome-like surface 47 with a projection 48 conformingexteriorly to the entrance portion of the igloo and rod portion 49 forhandling or controlling the movement of the male die. In using thecombination, a measured amount of moldable material, such as plaster ofParis, is placed in the bottom 50 of the mold defining the cap portionof the igloo and the male die brought down into the mold to applypressure to the moldable material causing it to flow into thecompartments of the female mold. After it has been made certain that allof the material has flowed uniformly to all parts of the mold, the maledie is removed and the material in the mold compartments furthersmoothed, if necessary, or excess material removed before it hascompletely set. Upon completion of setting the thus-produced curvedpieces are removed by manipulating the mold segments, such as 30, 31 and32, in order to dislodge the pieces via the distortion of therubber-like membrane.

While the foregoing mold combination has been described in conjunctionwith the production of a toy igloo, it is to be understood that asimilar mold combination of larger dimension could be used in theproduction of inhabitable structures. In such instances, the rubber-likemembrane need not be used. The male and female die mold could be madefrom metal, such as cast iron or steel. The mold segments, e.g. 30, 31and 32, etc., and the partitions integral therewith might be madeseparately from cast iron and fitted together and held in place byback-up segments, such as 27, 28 and 29 shown in Fig. 9a. A mold of thistype construction could be used in the production of curved segmentsfrom heat curable materials, such as mixtures of wood fibers andresin-type binders, e.g. phenolformaldehyde resin and the like.

In utilizing the mold combination for the production of heat cured woodproducts, the male die is adapted to be heated by a liquid or steamcarrying coil buried beneath the die surface periphery. The male die (beit dome shaped) may comprise an outer shell of metal with a coil oftubing on its under surface, the tubing being backed up by an insulatingor other suitable material. Thus, in producing curved wood panels fordome-like structures, a mixture of wood fibers (e.g. sawdust) and a heatcurable resin (for example from about 3% to 12% resin) is distributedthroughout the inner periphery of the female mold, the heated male dieinserted and the material simultaneously pressed and cured. The male dieis withdrawn and the pressed wood composition cooled and then removedfrom the mold by manipulating the mold segments. Because of thecompressibility of the wood fibers, the mold compartments would bedeeper, i.e. the partitions would rise to a higher height from thesurface of each compartment. To accommodate the male mold snugly, slitsmay be provided in the surface of the male mold (horizontally andvertically) into which the partitions would fit when the dies arebrought together.

In making curved segments by the foregoing method, it is preferred thatthe segments be reinforced to improve their strength. This can be doneby imbeddingcurved.

angle iron in the segments. The angle iron canbe indexed in positionwithin the mold compartments and, the composition mixture pressedaroundit. The angle iron can then be used to eflect connection, betweencurved segments in'providing permanent structures.

Curved building segments with. imbedded angle iron are shown in Figs.and 11,. connected curved segments" 52 and 53.: with angle irons 5,4 and55 via abutting flanges 54a, and 55a, respectively, runningtherethrough. An angle. iron 56- (for further reinforcement) is shownrunning transverse to 54, there being a corresponding one (not shown.)transverse to angle iron 55. In producing this type of curvedconstruction element, bolts 57 and 58 running through. angle irons 54and 55 are positioned through said reinforcing angle irons prior tomolding, the exposed threads of the bolts being protected by a woodenplug. After the segments have been molded, the wooden plugs are removedand a pair of internally threaded sleeves 59 and 60 connected to eachbolt, the sleeves being connected bya universal joint (e.g. 61) tothreaded L-shaped' bolts 62, 63, adapted to receive turn buckle 64. Thistype of connecting means enables the curved building segments to befitted together and secured permanently.

Fig. 11 shows another embodiment for connecting together curved segments65 and 66, also reinforced interiorly by angle irons 67 and 68 withother angle irons running transverse thereto, such as 69. Holes forreceiving bolts are provided for in the curved segments during pressingby means of stepped cylindrical wooden plugs which pass through theangle irons and about which the material is molded. The plugs areremoved after curing leaving a hole adapted to receive bolts 70 and 71for holding the curved securing plate 72 shown more clearly in Fig. 12.Instead of using removable wooden plugs to form bolt holes in thebuilding segments, metal sleeves adapted to receive bolts can beimbedded during pressing and allowed to remain permanently in thefabricated segments. This would enable a connection involving a securingplate on both sides of the two segment surfaces with bolts passingthrough the imbedded sleeves and the metal plates, thus making for rigidstructures via abutting flanges 67a and 68a of the angle irons.

Figs. 13 and 14 illustrate another type of connecting means for holdingcurved segments 75 and 76 together via imbedded angle irons 73 and 74characterized by boltable flanges 77. The curved segments 75 and 76 haveat their abutting edges recesses 79 and 80 which in cross section appearas large recess 81 (Fig. 13) in which flanges 77 are exposed enablingthem to be connected by bolts 78. This type of connecting means ispreferred over those of Figs. 10 and 11 for appearances sake.

As has been mentioned hereinbefore, the present invention is alsoadaptable to three-dimensional puzzles. In this connection, theinvention can be adapted to the making of a World relief map in the formof a spherical globe. Two molds would be used divided into a pluralityof compartments for each half of the globe, the molding surface beingreliefed with a negative reproduction of the world. Thus, by using twomolds, and operating each separately, a plurality of curved segments canbe produced, e.g. from plaster of Paris or other molding material,capable of being fitted together by holding means to form a hollowspherical object containing a relief of the world even down to themountains. Or if a dome-like building is desired showing reliefs ofwindows, doors and the like, the interior mold surface can be reliefedwith such surface configurations. Even three dimensional picture puzzlescan be made in the same way, that is with the pictures imprinted bymolding on the curved surface Fig. 10 illustrates two of the dome. Suchpuzzles would have'considerable educational value for; children.

Summarizingfan'eduoational aspect of the invention, a method is providedfor producing a plurality of threedimension'ally curved building blocksegments. capable of being fitted togetherto form a toy dome-likestructure ofhollow configuration comprising casting a settable material,such as plaster of Paris, against a flexible inner mold surface ofhollow dome-like configuration divided into molding compartments by aseries of vertical and horizontal partition ribs. The material in thecompartments is smoothed flush with the top of the partitions and theirallowed to set to form curved building block segments which arethereafter removed by simply flexing or distorting the rubber-likecasting surface. The shape of the segments is characterized in that theycan be assenibled into a dome-like structure, e.g. into an igloo-.-

While the presentv invention has been described in conjunction withpreferred embodiments, it is to be understood that modifications andvariations may be resorted to without departing from the spirit andscope of the invention, as those skilled in the art will readilyunderstand. Such modifications and variations are considered to bewithin the purview and scope of the invention and the appended claims.

I claim:

1. A molding assembly for the production of a dome structure, saidassembly characterized by a molding surfaceof dome-like configurationwherein said molding surface is manipulatively movable to' dislodgecomponents molded, thereagainst,, a plurality of annular ring partitionshorizontally spaced and integral with said molding surface, and aplurality of arcuately curved partitions longitudinally disposed alongand integral with the molding surface and which lie in planes containingthe polar axis of said dome-like molding surface, the intersectionsformed by the horizontally and longitudinally disposed partitionsdefining a plurality of molding compartments adapted to receive asettable material for molding into a plurality of segments from which adome can be fitted together.

2. A molding assembly for the production of a dome structure, saidassembly characterized by a molding surface of dome-like configurationwherein at least said molding surface is comprised of elasticrubber-like material distortable to dislodge components moldedthereagainst, a plurality of annular ring partitions horizontally spacedand integral with said molding surface, and a plurality of arcuatelycurved partitions longitudinally disposed along and integral with themolding surface and lying in planes containing the polar axis of saiddomelike molding surface, the intersections formed by the horizontallyand longitudinally disposed partitions defining a plurality of moldingcompartments adapted to receive a settable material for molding into aplurality of segments from which a dome can be fitted together.

3. A flexible unitary mold for the production of a dome structurecomprising a shell of elastic rubber-like material of dome-likeconfiguration at the molding surface thereof, a plurality of flexibleannular ring partitions horizontally spaced and integral with saidmolding surface, and a plurality of arcuately curved partitionslongitudinally disposed along and integral with the molding surface andwhich lie in planes containing the polar axis of said dome-like moldingsurface, the intersections formed by the horizontally and longitudinallydisposed partitions defining a plurality of molding compartments adaptedto receive a settable material for molding into a plurality of segmentswhich can be dislodged by distorting said mold after the material hasset.

4. A method of producing a dome structure which comprises forming amolding surface of dome-like configuration wherein said molding surfaceis manipulatively movable to dislodge components molded thereagainst,dividing said molding surface into a plurality of molding compartmentsby horizontally spacing a plurality of annular ring partitionslatitudinally about said molding surface and longitudinally disposing aplurality of arcuately curved partitions whereby said longitudinallydisposed partitions lie in planes containing the polar axis of saidmolding surface, casting a settable material within each of said moldingcompartments against said mold surface, smoothing said settable materialflush with the top of said partitions defining said molding components,setting said molding material, and removing the set molding material assegments characterized by three-dimensionally curved surfaces from thecompartments by manipulating said molding surface.

5. A method of producing a dome structure which comprises forming aback-up molding surface of domelike configuration from a plurality ofmolding elements, said back-up molding surface being covered with alayer of elastic rubber-like material manipulatively distortable todislodge components molded thereagainst, dividing said molding surfaceinto a plurality of molding compartments by horizontally spacing aplurality of annular ring partitions latitudinally about said moldingsurface and longitudinally disposing a plurality of arcuately curvedpartitions, whereby said longitudinally disposed partitions lie inplanes containing the polar axis of said molding surfaces, casting asettable material within each of said molding compartments against saidmold surface, smoothing said settable material flush with the top ofsaid partition defining said molding components, setting said moldingmaterial, and removing the set molding material as segmentscharacterized by three-dimensionally curved surfaces from thecompartments by distorting said molding surface.

' ulatively movable to dislodge components molded thereagainst, dividingsaid molding surface into a plurality of molding compartments byhorizontally spacing a plurality of annular ring partitionslatitudinally about said molding surface and longitudinally disposing aplurality of arcuately curved partitions, whereby said longitudinallydisposed partitions lie in planes containing the polar axis of saidmolding surfaces, casting a settable material within each of saidmolding compartments against said mold surface, smoothing said settablematerial flush with the top of said partition defining said moldingcomponents, setting said molding material, and removing the set moldingmaterial as segments characterized by three-dimensionally curvedsurfaces from the compartments by distorting said mold.

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